污泥焚烧中重金属和碱金属气固转变区域

Study of partition of heavy and alkali metals during sewage sludge incineration

通过污泥焚烧试验研究了尾部烟道不同温度区域重金属和碱金属的分布,发现每种金属都有自己的气固转变区域.因此可以通过温度控制对这些金属进行分类,从而达到分离利用的目的.根据金属的气固转化温度,可将它们分成四类:A类金属在温度高于600℃以上的区域开始从气态转变成固态,包括Zn,Cd,P;B类元素转变温度为400℃,有Pb和Cu;C类有Na和Mg,其转变温度为300℃以下;D类在300℃到400℃时转变,主要有As.

In order to study the distribution of heavy and alkali metals at different temperature zones during sewage sludge incineration, an experiment was carried out on a bench scale combustor. The results indicated that every metal has their own gas-solid conversation temperature. It was possible to separate and reuse the metals in fly ash. The heavy and alkali metals can be divided into four groups on the basis of their transformation temperatures： group A, being converted into condensed phase above 600℃, included Zn, Cd and P; the conversion temperature of group B, including Pb and Cu, was above 400℃; Na and Mg were among group C, the condensation temperature was lower than 300℃; As for group D, As was found, with transformation temperature between 300℃ and 400℃.